This invention relates to a liquid crystal projector provided with an illumination, optical system including a polarization changing optical system and an optical integrator.
In the conventional field of liquid crystal projectors, there has been known a liquid crystal projector provided with an illumination optical system including a polarization changing optical system and an optical integrator to obtain a bright projected image having a uniform distribution of illuminance as disclosed in Japanese Unexamined Patent Publications Nos. (HEI)6-265887 and (HEI)7-120753.
However, the above liquid crystal projector has a problem that the polarization changing optical system is likely to be degraded by heat because of its position in proximity to a light source.
Further, in the above liquid crystal projector, a polarization change is completed in a position more toward the light source than where the beam is incident on the optical integrator, the dimension of the illumination optical system in a direction normal to its main optical axis disadvantageously increases. Furthermore, since spaces are required to install the polarization changing optical system and the optical integrator, respectively, the dimension of the illumination optical system in a direction along its main optical axis disadvantageously increases. There are also problems that the polarization changing optical system making effective use of the light from the light source has a large size and a complicated construction.